Drum switch



A ril 2, 1935. A." HoRowrrz 1,996,244

DRUM SWITCH Filed Feb. 24,- 1933 2 Sheets-Sheet l ATTORNEY April 1935- A. HOROWITZ 1,996,244

DRUM SWITCH Filed Feb. 24, 1933 2 Sheets-Sheet 2' INVENTO/S ALEX/MORE #0501177 Z ATTORNEY Patented Apr. 2, 1935 UNITED STATES PATENT OFFICE DRUM SWITCH Application February 24, 1933, Serial No. 658,310 In Germany February 25, 1932 3 Claims.

An object of my invention is to provide a drum type of switch which may be constructed with the minimum number of component parts and may be easily assembled and taken apart.

A further object is to provide a switch in which the movable contacts may be compactly arranged and easily connected together with each other to provide a large number of different possible circuit connections.

A still further object is to provide a switch in which both the stationary and movable contacts are mounted in units formed of insulation material and any desired number of which may be easily clamped together to form a switch of the requisite number of contacts.

The rotor of the switch according to the invention consequently consists of mutually equal units. This affords a great advantage in manufacture. Owing to the fact that the plurality of mutually insulated contacts may be provided at the circumference of the units, there are a large number of possibilities of connecting these contacts with the contacts co-operating with the rotor. This number is still larger when considering that the contacts on the rotor may also be connected to one another so as to form separate groups, e.'g. by means of connecting wires soldered on to the contacts. This is possible owing to the fact that the contacts protrude from the surface of the units so that the connecting wires may be provided between them. The protrusion of ,the contacts affords the additional advantage that when the rotor is turned the stationary contacts or brushes co-operating with the contacts do not come into contact with the insulating material so that these contacts cannot become soiled or fuse together.

In one particular embodiment of the invention the rotor units are formed in such manner that they are centered on each other and cannot be turned tangentially relatively to one another while after mounting the recesses provided at the circumference. of the units come to lie in alignment. A rotor formed of a plurality of such units consequently has a plurality of grooves which extend in the longitudinal axis of the rotor and the number of which is equal to that of the recesses. In said grooves may be hooked correspondingly formed contact members. The rotor units are preferably furnished with such 'a bore, e. g. a square one, that when mounted on the rotor shaft they cannot be turned. This shaft preferably consists'of two parts viz. of a hollow shaft having a section corresponding to the bore of the units and of a cylindrical shaft connected to the former shaft.

For constructing a switch of determined length one only need have at ones disposal-a hollow rod of required section from which a portion is cut off. On this portion are mounted the rotor units. Furthermore, from a round rod is taken the required length and this length of rod is slid into the hollow rod whereupon the round rod and the square one are locked on each other in the correct mutual position, for example by means of a wedge. The length of the round rod need not be equal to that of the square tube. The round rod may be taken of such length that it protrudes on both sides from the switch so that the latter may be coupled at both ends to another part. The solid rod, the drivingshaft proper, may be furnished in this case with the means necessary for mounting the rotor in a casing.

If the rotor shaft is made in one piece, one wants for each length of the switch a shaft which requires special working. The units forming the rotor are secured to one another by means of a plurality of bolts traversing all the units. The latter are furnished for this purpose with holes, which in mounting the units come to lie in alignment.

Furthermore, there must be provided means for locking the rotor in the different switch positions. An advantageous form of construction of these means will be described with reference to the drawings.

In accordance with the fundamental idea of the invention the stationary contacts co-operating with the rotor contacts are preferably also secured in unitary holders.

For the construction of a so-called tapping switch it is advisable to provide at the circumference of the separate rotor units more than two contacts, owing to which the dimensions are considerably decreased while in comparison with a switch in which the rotor units co-operate only with two contacts provided at their circumference the number of possibilities of connection is considerably increased.

The fundamental idea of the invention will be explained more fully with reference to some forms of construction given by way of example.

Figure 1 represents a lateral elevation of a switch according to the invention.

Figure 2 is a plan view of the corresponding rotor.

Figure 3 is a front elevation.

Figure 4 is a perspective view of a,v holder for a stationary contact.

Figure 5 is a diagrammatical section through the longitudinal axis of the switch.

Figure 6 is a view of one side of a rotor unit.

Figure 7 is a view of the other side.

Figure 8 is an elevation normal to the axis of the rotor unit.

Figures 9 and 10 represent the rotor contact members.

Figure 11 represents a rotor furnished with two separate contact bodies clamped between the rotor units.

Figure 12 is a front view of this rotor.

Figure 13 shows a special construction having a plurality of stationary contacts provided at the circumference of the rotor unit.

The switch according to Figure 1 consists of two plates l and 2 between which stationary contact members 3 (see Figure 4) are clamped by means of screw bolts 4 and in which the shaft 5 of the rotor is journalled (see Figure 5). The contact holder 3 which consists of insulating material, has secured to it a contact spring 7 by means of screw 5, by which also a terminal 3 is secured to said holder.

The rotor (see Figure 2) is formed of insulating unitary discs 9 which are more distinctly shown in Figures 6, 7 and 8. The protruding portion to of an insulating disc 9 engages a recess iii of the next disc. The discs are arranged in such manner that they cannot be turned tangentially relatively to one another. The grooves H2 at the circumference of the discs come to lie in alignment so that the finished rotor has in its circumference a plurality of grooves 93 extending in the longitudinal direction of the rotor. (Figure 2.)

In these grooves are hooked contact members it which may be of any length desired. The lips l5 come to lie in cavities it of the discs. The mode of attachment is very favorable because there are no screws which may work loose. The lipe ll (Figure 10) serve for soldering thereto connecting wires it, if desired (Figure 2).

The bores I9 of the discs, which in mounting also come to lie in alignment, for the passage of two bolts Ell destined for securing the discs 9 on to each other.

The discs are furnished with a square bore. In a recess 2! is laid a laminated spring 22 (Figure 5) inorder to eliminate the play existing between the discs and the shaft 5. -The number of recesses 62 at the circumference of the discs is on the one hand determined by the dimensions of the contacts I d and on the-other hand there must remain a determined distance between the recesses, which distance dependently on the value of the tension, may be larger or smaller. The square shaft 5 is slightly turned off at both ends so that cylindrical extensions 23 (Figure 5) are produced which serve for journalling the shaft and for centering the rotor relatively to the casing.

A groove provided in one of the extensions 28 is engaged by a pin 25 secured in the hollow actuating shaft 28. This pin couples the two parts 2 3 and 5 of the rotor with one another. The angle of rotation of the shaft is limited owing to the fact that when the rotor is being turned the pin 25 butts against a pin 25. In order to lock the shaft 24 in axial direction, the pin 25 is enclosed between the plate 9 and the cover 28 secured to said plate by means of screws 2?. the shaft is mounted an actuating knob 29. In a cavity 30 of the rotor is resiliently arranged a ball 3! which in the difierent positions of the switch comes to lie in cavities 32 of the plate l common holder.

so that in the switch positions the rotor is locked relatively to the plate I.

It is evident that the switch according to the invention affords a great number of possibilities of connection. If it is desired to construct the switch in such manner that the contacts closed by means of the switch are interrupted in succession and not simultaneously, it is advisable to clamp one or more contact bodies 33 according to Figures 11 and 12 between the rotor discs.

The stationary contacts 34 co-operate with the circumference of the contact bodies 33. In this circumference are provided cavities 35.

By altering the lengths i and i it is possible with a suitable connection of the connecting wires to obtain the successive interruption of a plurality of contacts closed by means of the switch.

Figure 13 represents diagrammatically a portion of a rotor co-operating with a plurality of contact springs providedat the circumference. Springs 36 are secured by means of screws 31 to insulating pieces 38 which are carried by a The rotor contacts 39 have a slightly different shape. it shows a shape by which it is rendered possible to connect simultaneously two of the circumference contacts.

What I claim is:-

1. In a switching device, the combination of a plurality of discs of insulating material, each of said disesbeing provided with a centrally located square shaped aperture and a plurality of longitudinally extending slots in its periphery, a plurality of contact members having portions engaging in said slots, a shaft having a square cross section passing through the central apertures of said discs, a compression spring engaging said shaft and the bounding edges of the central apertures of said discs and means for rotating said shaft.

2. In a switching device, the combination of a frame having spaced apart parallel end members, one-of said members being provided with a plurality of apertures arranged on an arc of a circle, a plurality of insulating discs each being provided with a. central aperture, a shaft passing through the apertures of said discs, means for rotating said shaft, one of said discs beingalso provided with a recess, a spring pressed ball in said recess and. arranged to seat in either of the apertures of said end member, each of said discs being also provided with a plurality of longitudinally extending slots, a. plurality of contact members having portions extending into said slots, and a plurality of stationary contact members arranged to be engaged by said first named contact members. v

3. In a switchingdevice, the combination of a plurality of discs of insulation material, each of said discs being provided with a plurality of Iongitudinally extending peripheral slots and a re-v cess formed in the end wall of the disc on each side of each of said slots, a plurality of contacts having radially extending portions projecting from the periphery of said discsand seated in said slots, each contact being also formed with two lugs at its end, said lugs lying in a plane substantially 90 degrees from the plane of the radially extending portions, and said lugs being seated in said recesses whereby said contacts are secured in position in said discs, a shaft connected to rotate said discs, and a plurality of stationary contacts arranged to engage said first named contacts.

ALEXANDRE HOROWITZ. 

